FI114223B - Plant for controlling turbulence of a pulp stream in an inlet box of a paper machine or equivalent - Google Patents

Description

114223

Apparatus for adjusting the turbulence of a mass flow in a headbox of a papermaking machine or the like 5

The invention relates to apparatus for controlling the turbulence of a mass flow in a headbox of a paper machine or the like.

10

Future papermaking processes will optimize production and product quality based on real-time measurement and control systems. In the headbox, a key measurable and adjustable quantity for paper quality formation is e.g. the degree of fluidization of the suspension. The degree of fluidization can be affected at turbulence level. In addition, the tensile strength ratio of the paper can also be influenced at the turbu-15 slope level. Turbulence is generated in the headbox by various geometric solutions, such as, for example, flow changes in flow channels.

When aiming to optimize the production quality and species-specific operating point, it is also possible to adjust the turbu-20 lensing level. Traditionally, the adjustment has been made by changing the headbox sets of different lengths. Such an adjustment always requires the machine to be stopped and a new heightsetter replaced. To make things easier, a new method of •,: turbulence adjustment is proposed for the headbox, which allows stepless adjustment of the lip jet turbulence .... * · level even while driving.

25> »·, The new control method consists of a turbulence generator whose flow velocity between the mass flows of the tube rows can be adjusted by means of axial; With wings rotating around Iin. Correspondingly, the adjustment can be made, for example, with valves.

'_ / · The turbulence generator has alternating horizontal tube rows with large diameter and: .'30 small diameter tubes. Tubes with small pipe diameters may be longer. "'· Than those with larger pipe diameters.

M * t * · »♦ 2 114223

In the disclosed method, the formation of turbulence simply depends on the size of the stepstream that the main flow experiences at the end of the small diameter tube rows. The size of the staircase is directly determined by the difference in flow rate of the mass flow between the rows. The larger the flow rate control, the higher the stage the main flow will see the end of the pie-5 smaller pipes, and the more turbulence will be generated. If, on the other hand, the flow velocities in the overlapping tube rows are set equal, the main flow will not see any stairs at the ends of the small diameter tubes, and thus no turbulence will occur at that point.

The invention is characterized by what is stated in the claims.

The great advantage of the disclosed method is its safety. Unlike the previous solutions, it does not. the solution requires moving parts in the delicate lip jet forming area at the lip duct and at the tail end of the turbulence generator at all.

15

BRIEF DESCRIPTION OF THE DRAWINGS The invention will now be described with reference to the accompanying drawings, in which some preferred embodiments of the invention are shown, but are not intended to be limited thereto.

Fig. 1A is a longitudinal cross-sectional side view of a headbox 10 of a paper machine or the like, such as a board machine according to the invention.

Figure 1B shows an enlarged scale area A of Figure 1A.

Figure 1C is a sectional view I-I of Figure IA.

: '' · Figure ID shows an enlarged scale of area B in Figure IA.

ti · 25 '... * Figure 2 illustrates the occurrence of turbulence in the flow velocity of the lip chamber by alternating columns of turbulence generator.

Fig. 3 shows an embodiment of the invention in which the tubes of the turbulence generator are all of the same length.

Il · * · »I · I · tl · t> · t» · t · • · 3 114223

Figure 4 illustrates an embodiment of the invention in which the flow rate V2 is controlled by valves in the smaller inner diameter tubes of the turbine generator.

Figure 5 illustrates an embodiment of the invention in which the valves of Figure 4 are replaced in the intermediate chamber 5 by a regulating device formed by a perforated plate at the mouth of the turbulence generator turbulence tubes.

Fig. 6 shows a more specific embodiment corresponding to the embodiment of Fig. 1A, in which one motor M1 moves adjacent slats simultaneously and at the same angle.

10

Fig. 7 shows an embodiment of the invention in a lateral cross-sectional view, with tube rows extending across the width of the headbox with two rows of tubes having a larger diameter. This is followed by a tube row of smaller inner diameter tubes and then again by two overlapping tube rows of larger inner diameter tubes. Thereafter, there is again a row of tubes having a smaller inner diameter and a flow cross section, and again at the top are two rows of tubes having inner diameters of a larger cross-section than the smaller inner diameter tubes of the mandrel below.

20 V. The headbox 10 of the papermaking machine or the like shown in Fig. 1A comprises a mass distribution 4t, y: log J1 and then a bellows 11, a bellows chamber E, a bellows chamber • * · turbulence generator 12 comprising a plurality of turbulence generator tubes 12ai, 12a2, · * ·, · *: 12a3, 12a4, 12as in tube rows. From the turbulence generator, the mass flow is led to the mouthpiece K and then through the lip opening A to the forming wire Hi.

1 t 1 • * I · «* *

Illustrated in Figure 1A, the headbox turbulence generator 12 comprises a turbulent

I I I

',, on the inlet side of the ducts, the mass flow regulators LI.

Flow regulators 13 may consist of flow-guiding pivoting * * * · slats 14ai, 14a2 ... They are arranged in the vertical section of the turbulence generator for each I »*, · · *, tube row 12aj , 12a2,12a3,12a4 and 12a5.

* · »« · T * · <t »I ·

I I

114223

Further, the tubes of the tube rows 12ai, 12a2,12a3,12a4 and 12a5 in the vertical section are formed such that a turbulence generator tube having a larger flow cross section is followed by a tube having a smaller flow cross section in a vertical row, followed by a tube cross section, relative to the previous row of tubes. A turbulence generator can also be used, with every third row being a tubular row of smaller cross-sectional area. Horizontally, the rows in each row have the same flow cross-sectional areas. According to the invention, the mass flow Li from the intermediate chamber E can be divided into overlapping turbulence generator tube rows by means of the regulators at the mouth of the tur-10 bulb generator so that a certain flow rate Li As the flow rate is increased to the smaller inner diameter tubes, the velocity of the flow 15 in these tubes tends to increase and thus the flow velocities in the overlapping tubes can be affected and at the outlet end of the respective turbulence generators the

20 The solution shown in Figure IA has overlapping tube rows for the turbulence generator •. 12ai, 12a2, 12a3, 12a4 and 12as are formed such that the overlapping tubing rows have a barrel, ·; bulldozer tubes with different cross-sectional flows.

Thus, the tube rows are so formed that the inner diameters of the tubes in the overlapping tube rows alternate. A larger row of tubes having a smaller inner diameter is followed by a tube row of 25 tubes having a smaller inner diameter, and so on. The flow from the intermediate chamber E is divided into said tube rows such that, by increasing the flow to a tube having a larger flow cross-section and inner diameter, for example, the flow in the immediate vicinity of said tube row is reduced to: · * *. 30 tubes of inner tube diameter. In the embodiment shown in the figure are tubular. * .. the rows 11a2 and 4 are smaller tubes with inner diameter and again 11a, 1a3 and 1 '. Lias tubes have a larger inner diameter relative to them. Intermediate chamber E is provided with 5114223 adjusting means 13 preferably lamellae or slats 14ai, 14a2, 14a3 and 14a4 in the tubular rows 12ai and 12a2; 12a2,12a3; 12a3, 12a4; Between 12a4, 12as. The slats 14ai and 14 & 2 ', 14a3 and 14a4 are mutually cooperative. The slats 14ai and 14a2 can be tilted towards each other or away from their inlet ends, and the slats 14a3 and 14a4 respectively can be tilted towards and away from each other simultaneously. Thus, the mass flow is divided into either larger inner diameter tubes or smaller inner diameter tubes and such that by increasing the flow, for example, larger inner diameter tubes, the corresponding amount decreases the flow into the smaller inner diameter tubes between the larger inner diameter tubes.

10

Figure IB is an enlarged scale area A of Figure IA.

Figure 1C is a sectional view I-I of Figure IA and Figure ID shows an enlarged scale area B of Figure IA.

15

As shown in Fig. 1B, the velocity difference between the flow V2 from the smaller inner diameter tubes and the flow Vi from the larger inner tube diameter is obtained by the adjusting device 13. When the flow rate Vi of pipes with a larger inner diameter is greater than the flow rate V2 with a smaller inner diameter. . Pipes having 20 diameters result in high turbulence and correspondingly lower turbulence of I * * 1 when the flow Vj is equal to the flow V2.

»* · I f I • * • * • * * • * ,,.,: Figure 2 illustrates the occurrence of turbulence at a flow rate V1 of · ·, ·· *. much larger than the flow velocity V2, that is, the larger diameters of the flow • · * · ·. · * ·. 25 having a significantly higher flow rate than the tubes V having a smaller inner diameter, entering the mouth chamber K into the flow V2.

• «♦ * * • ''; Fig. 3 shows an embodiment of the invention in which the tubes of the turbulence generator (12) • · ·; '·. 12au, 12ai.2 ...; 12a2.i, 12a2.2 are of the same length, but in which the flow cross-sections of the embodiments lie between the tubes of the overlapping rows of tubes and alternate as in the embodiment of Fig. 1A.

• * · »t ·» · 6 114223

Figure 4 shows an embodiment of the invention in which pipes with a diameter smaller than the flow rate V2 are controlled by valves U1, U2.

Figure 5 illustrates an embodiment of the invention in which the valves U1 and U2 are replaced by a hole 15 in a plate 15 which adjusts the flow rates while simultaneously reducing the flow throttling to or from the tubes 12a2, 12a4 by the amount of flow to the tubes 12a, 12a3, 12a5.

The perforated plate 15 is arranged to be movable by the motor Mi 0 in a linear fashion in the directions indicated by the arrow S1, whereby the openings 15a1, 15a1a in the perforated plate 15 limit the flows to the overlapping tube rows. In this case, the flows are controlled such that when throttling the flow to, for example, smaller diameter pipes, the throttling is simultaneously reduced to larger inner diameter pipes or vice versa.

Figure 6 shows an embodiment of the invention in which motor M1 moves all slats 14ai, 14a2, 14a3 and 14a4 simultaneously so that the slats 14ai and 14a2 pivot towards each other at a particular motor drive and the slats 14a2 and 14a3 respectively move towards one another or rotate the p slats 14a and 14a2 away from one another at their ends and slats 14a3 and 14a4 respectively away from each other. Fig. 6 shows an adjusting drive in which the ends of the slats 14ai, • t 14a2 and respectively the slats 14a3, 14a4 are moved towards each other.

•

Figure 7 illustrates an embodiment of the invention in a vertical cross-sectional view with rows of tubes extending across the width of the box with two larger halves on top. · 1. 25 rows of tubes 12aj, 12ai 'consisting of reeds. This is followed by a tube row 12a2 of smaller inner diameter tubes, and then again by two overlapping tube rows 12a3, 12a3 'of larger inner diameter tubes. This t1 is the pipe line I »·: of tubes having a smaller inner diameter and a flow cross-section. 12a4 and at the bottom there are again two rows of tubes 12as, 12as', the inner diameter of the tubes of which are of a larger cross-section than the tubes 1 above ;; line with smaller inner diameter pipes.

I · * «· ♦ 114223

As shown in Fig. 7, adjusting means 13, preferably slats, are arranged on the inlet side of the turbulence generator 12, which divides the flow either into two tube rows of larger cross-sectional tubes or into one tube rows of smaller cross-sectional tubes. The tube rows 12a2, 12a4 of the smaller cross-sectional tubes 5 in the embodiment of Fig. 7 extend further into the head cone lip cone K than the tubes of the larger-cross-sectional tube rows 12ai, 12ai ', 12a3, 12a3, 12a5, 12a'. It is also possible to have an embodiment in which two or more tubes of smaller inner diameter are adjacent and in which more than two tubes having a larger inner diameter are in parallel. It is essential that 10 have at least two adjacent tubes having a different flow cross-sectional area, wherein the flow rates of the masses flowing in the tubes are adjusted relative to each other to adjust the turbulence at the output end of the turbulence generator.

»· ·» * ·

Claims (10)

A headbox (10) for a papermaking machine or the like, comprising a pulp distributor (J1) followed by a downstream bellows (11) and then an intermediate chamber (E) followed by a turbulence generator (12) comprising a plurality of overlapping tube rows (12ai, 12a2) 12a3,12a4,12a5; 12ai, 12ai ', 12a2, 12a3,12a3', 12a4, 12a5,12as'), wherein each row of tubes comprises a plurality of parallel turbulence generator tubes (12au, 12ai.2, 12ai.3 ...; 12a2.i, 12a2.2, 12a23- ..) and wherein the turbulence generator (12) has at least two rows of headbox transverse tubes having different internal diameters, the feeling 11 u that the turbulence generator (12) 12) comprises a control device (13) for controlling the flow rates of the mass flows (Li ', Li') to the respective tube rows relative to each other, wherein the outlet of the turbulence generator (12) in this case the turbulence of the mass flow is affected by this adjustment. 15 Headbox according to Claim 1, characterized in that there is a control device (13) which is arranged to reduce the flow velocity in the tubes of the smaller inner diameter tubes and respectively to increase the flow in the tubes of the larger diameter tubes or vice versa. »· T ·: 20 * · t · Headbox according to Claim 1 or 2, characterized in that the control means (13) consist of valves (U1, U2 ...) in the inner diameter tubes of the turbulence generator, by means of which the mass flow can be throttled to the desired extent, · ·. blade. »· 25 Headbox according to Claim 1 or 2, characterized in that the adjusting means (13) consist of slats (14ai, \ t <14a2, 14a3, 14a4) at the inlet end of the turbulence generator located in the intermediate chamber of the turbulence generator (12). # · · '# (E) between the rows of the turbulence generator. 30 a · • · · 9 114223 Headbox according to claim 4, characterized in that the slats (14a and 14a2) are cooperative and are simultaneously moved towards or away from each other at their ends and the slats (14a3 and 14a4) respectively are cooperative and also moved towards and away from one another, wherein the slats 5 direct the flow to the various tube rows of the turbulence generator turbulence tubes by reducing the flow of the slats to the other tube rows by an equivalent amount of mass flow to the other tube rows above and / or below said tube rows. Headbox according to Claim 4 or 5, characterized in that the slats 10 (14ai, 14a2, 14a3, 14a4) are moved by a motor (Mi) which engages the toothed wheels (16ai, 16a2, 16a3, 16a4) via the slats (14ai, 14a2). , 14a3) shafts. Headbox according to Claim 1 or 2, characterized in that the regulating means (13) consist of a hole plate (15) arranged in the intermediate chamber (E) at the mouth of a turbulence generator to regulate the flow between the different tube rows. Headbox according to Claim 1 or 2, characterized in that the tubes (12a2, 12a4) of the tube rows (12a2, 12a4) having a smaller inner diameter of the turbulence generator (12),. longer than their respective inner diameters and having a flow cross sectional area I 1 «; 20 (12ai, 12a3, 12a5). • 1 1 8 114223 Headbox according to claim 1 or 2, characterized in that the turbo-. ··. Lens generator (12) in overlapping rows of headbox width. (12ai, 12a2 · ..) are tubes of different size with respect to their flow areas, with • · 25 in the overlapping tube row alternating tube inner diameters such that the tubes of the smaller inner -.... turbulence generator tube row follow .1 · 1st tube with larger inside diameters. i · ' Headbox according to Claim 1 or 2, characterized in that the turbine lens generator comprises at least one row (12a2,12a4) of tubing extending across the width of the headbox, the tubes having a smaller inner diameter than at least one above and / or below it. two overlapping tubes of a row of tubes (12ai, 12ai ', 12a3,12a3', 12a5,12a5 ') and that the smaller diameter tubes of the tube row (12a2,12a4) extend further into the lip cone (K) than those of a larger inner diameter and flow cross section tubing rows (12ai, 12ai ', 12a3,12a3', 12a5,12a5 '). 114223 * »·% I« ♦ «» · * 1 · · ·> · <»♦ I I * · • ► ·« · •>> 1 • · «» »• • 11 114223